If you order one of the "Classics" at PW Pizza -- the pepperoni, say -- what arrives at your table looks like nothing so much as a pepperoni pizza. This is more remarkable than it might seem. In the past few years St. Louis has seen an evolution in our pizza sensibilities -- an evolution or maybe an arms race, pizzas slid into wood-fired brick ovens that cook at six, no, seven, no, eight hundred degrees.